Centaur ILF limbs brace height

[jeffg]

I read different post where they set brace hieght on the Centaur limbs @ 7.5 inches and they are quite
 I have a pair of med.  on Titan 2 riser that are noisy until the brace height gets to 8.375. Does the higher brace realy effect anything, speed or forgiveness ect?

[BAK]

You might loose a bit of the speed but not too much.

[nineworlds9]

What are you using for silencers Jeff?  For carbon bows the only way to go IMHO is well made rubber whiskers or really dense wool like Navajo or maybe Hush Puppies, but my first choice would be rubber. Fur just isnt dense enough to dampen the ping, frankly IMHO fur belongs on Hill bows or selfbows that are already quiet.  That and a metal riser will also have its own kind of resonance vs wood or phenolic.  

The problem with most ILF risers is the pad angles are made for recurve limbs, and so with most ILF longbow limbs you end up with high brace heights.  Border solved this by purposely making the limb butts on their Raptor longbow limbs thicker with an angle that forces the brace height back down to the 6-7.5 range which most LB guys are used to.    

I think the high brace you're seeing is mostly a sort of optical illusion because of the pad angles.  You might lose a very few FPS just cause the limbs are a bit more preloaded for the resultant draw length, but I doubt it's worth worrying about.

[damascusdave]

As Chuck implies making statements about ILF mixed combinations is like swimming with the White Sharks...eventually you will get bitten

DDave

[jeffg]

I am using Jims string silencers. Maybe if I go to 14 strand B97 it would help.

[nineworlds9]

Ditch the D97 and try a string made from Fury, BCY-X, or Rhino.  D97 IMHO is obsolete, the other 3 I mentioned have pretty well zero stretch and are above all super quiet when made right.  Remember the kickass string I had made for the Tuktu?

[jeffg]

It has a Centaur string on her now. And I do rember the great string that was on the bow I should have kept.

[nineworlds9]

jeff if it's a Centaur string then it's gotta be Rhino or Fury, and well made, going to D97 def shouldnt see any benefit IMHO.  what's your arrow GPP?

[jeffg]

Its 8.6. And it is only getting in the 175 rang. 47#@ 27". The TT Carbon extreme BF are in the 185fps 46"@27".

[nineworlds9]

That Titan, I studied some pictures of it.  It may just be too deflexed with relaxed pad angles to do those limbs justice.  I bet they would do better on a Zipper ILF riser LoL.  Jeff, how much more poundage are they gaining with the bolts cranked all the way down?  also, your arrows are on the lighter side.  Just adding a bit of weight to hit 10gpp will do a lot to quiet things down.  How low of BH can you go to before the limbs start to flop around?

[nineworlds9]

That Titan, I studied some pictures of it.  It may just be too deflexed with relaxed pad angles to do those limbs justice.  I bet they would do better on a Zipper ILF riser LoL.  Jeff, how much more poundage are they gaining with the bolts cranked all the way down?  also, your arrows are on the lighter side.  Just adding a bit of weight to hit 10gpp will do a lot to quiet things down.  How low of BH can you go to before the limbs start to flop around?

[nineworlds9]

also, for 27" draw length those numbers aren't terrible.  I wouldnt expect to get much more than 185-189 out of them at 10gpp and drawn to 28 depending in how clean the release is.

[jeffg]

Actually I believe Jim designed them using a Titan 2 riser I no for a fact that he uses one to build the limbs.
With them cranked all the way in I pick up 2#. I will tack a picture of them a 7.5" brace and at 8.250. At 7.5 there isn't very much preload if any. At 8.250 you can see the limbs are preloaded some
 
 
First is 7.5 #2 8.5

[nineworlds9]

you know you jogged my memory and you are right.  the first picture at 7.5 looks correct to me, I'm surprised it would be loud.  the second pic they def shouldnt need that much load in them and it will rob speed.  if the limbs are stable at 7.5 with not too much flop/ good vertical stability I say just try a bit more point weight and some rubber whiskers, and make sure theres not too many twists in the string.  too many twists adds noise.

[jeffg]

Tomorrow I will try some of you suggestions.

[jeffg]

This as good as I can get it 49#@27" 9.2 grains per pound 181 FPS. This is what I thought it should be Thanks Chuck and the rest of you.

[Orion]

I dunno.  The titan riser was designed for recurve limbs and has a fairly obtuse limb pad angle. Longbow limbs just aren't going to work that well in it, IMO.

In fact, most ILF risers are designed for recurve limbs and have relatively obtuse limb pad angles.  Though longbow limbs will shoot out of those risers, most don't get the best performance out of the limbs IMO.

A while back, Jim Belcher at SkyArchery said he was working on a longbow ILF riser design.  Don't know if he's brought it to market yet or give-up on the idea.  

[Gil]

[Gil]

Try moving the silencers towards the center or try a 1/3 bottom and 1/4 top for the silencers.

[forestdweller]

Originally posted by jeffg:
I read different post where they set brace hieght on the Centaur limbs @ 7.5 inches and they are quite
 I have a pair of med.  on Titan 2 riser that are noisy until the brace height gets to 8.375. Does the higher brace realy effect anything, speed or forgiveness ect?

I just wanted to comment on your brace height comment. I'm of the opinion that a higher brace height is not any more forgiving than a lower brace height.

The arrow is on the string for such a brief amount of time to the point where any flaws are going to show up regardless of what your brace height is.

Personally I'd try to get that brace height as low as possible before it starts to slap your arm.

Sure you may only gain 2-4 fps but any amount of speed you can gain is useful and I can notice a difference between 2-4 fps.

Not to mention the draw becomes significantly smoother the lower you can go in brace height so it's a win win.

Noise might be of concern but how quiet are you trying to get your bow?

As long as you are not getting any limb slap and just a slight low twang personally I'd not worry about the sound. The sound of the string coming off the fingers will be louder than any slight twang you will get.

Silencers and limb pad's are just another thing to worry about that also effect tune and can fail you in the field and I try to avoid them at all costs.

There's other ways to make a bow quiet like cleaning up the release and proper grip pressure and arrow weight along with string material.

With silencers you get almost no feed back on your shot in terms of noise as well.

You'd be surprise at how noisy you can make a bow with a poor release, poor grip pressure/bow hand placement, and an arrow that is not tuned for the bow.

You'd also be surprised at how quiet you can get the bow when you nail all of those things which is important for shot feedback.

Just my take on it.